226 research outputs found
Starting a business during a recovery: this time, it's different
Business cycles ; Economic conditions
Employment dynamics during economic recoveries
Employment turnover was significantly lower following the Great Recession than following the previous two recessions.Employment
Frictionless contact formulation by mathematical programming technique
The object of the paper concerns a consistent formulation of the classical Signorini's theory
regarding the frictionless unilateral contact problem between two elastic bodies in the hypothesis of
small displacements and strains. A variational approach, employed within the symmetric Boundary
Element Method, leads to an algebraic formulation based on nodal quantities. The contact problem
is decomposed into two sub-problems: one is purely elastic, and the other pertains to the unilateral
contact condition alone. Following this methodology, the contact problem, faced with symmetric
BEM, is characterized by symmetry and sign definiteness of the coefficient matrix, thus admitting a
unique solution.
The solution of the frictionless unilateral contact problem can be obtained
- through a step-by-step analysis utilizing generalized quantities as check elements in the zones of
potential contact or detachment. Indeed, the detachment or the contact phenomenon may happen
when the weighted traction or the weighted displacement is greater than the weighted cohesion
or weighted minimum reference gap, respectively;
- through a quadratic programming problem based on the minimum of the total potential energy.
In the example, given in the paper, the detachment phenomenon is considered and some
comparisons of the solution between the step-by-step analysis and the direct approach which utilizes
the quadratic programming will be shown
PBO textile embedded in FRCM for confinement of r.c. columns
Results of experimental tests on two reinforced concrete columns confined with PBO-FRCM jacketing subject to axial
load and bending moments are presented, showing the effectiveness of the confinement system. Comparison of test
results against theoretical results derived by a fiber model stress the ability of the confinement system to enhance both strength and deformation capacity of the confined concret
Active macro-zones algorithm via multidomain SBEM for strain-hardening elastoplastic analysis
In this paper a strategy to perform strain-hardening elastoplastic analysis by using the
Symmetric Boundary Element Method (SBEM) for multi-domain type problems is shown. The
procedure has been developed inside Karnak.sGbem code by introducing an additional module
Meat quality of Kuruma prawn (Marsupenaeus japonicus): preliminary evaluation
Among the peneids, Marsupenaeus japonicus, a cold-temperate species, carnivorous, is the mostly cultured prawn in Italy and in the Mediterranean Sea basin, thanks to the good adaptability to the temperature and salinity variations, to the good resistance to the manipulations (better resistance out of water), to its appreciate nourishing qualities and to the good growth rate (Lumare, 1998).Whereas the literature on cultured fish fillet is rich (Gjedrem, 1997; Lanari et al., 1999; Parisi et al., 2003), few are the information about the shrimp meat quality traits.Therefore, the present work aimed at typifying the variations of the meat quality characteristics in shrimps from semi-intensive (supplemented with an artificial diet) or extensive rearing systems
Observation of a molecular muonium polaron and its application to probing magnetic and electronic states
We thank the Engineering and Physical Sciences Research Council (EPSRC UK) for support via Grants No. EP/M000923/1, No. EP/K036408/1, No. EP/I004483/1, No. EP/S031081/1, and No. EP/S030263/1. L.L., S.S., D.J. and G.T. acknowledge also support from STFC-ISIS Neutron and Muon Source and Ada Lovelace Centre at STFC-SCD. We acknowledge use of the ARCHER (via the U.K. Car–Parrinello Consortium, EP/P022618/1 and EP/P022189/2), U.K. Materials and Molecular Modelling Hub (EP/P020194/1), and STFC Scientific Computing Department's SCARF HCP facilities. We acknowledge support from the Henry Royce Institute. This work was also supported financially through the EPSRC Grant Nos. EP/ P022464/1, and EP/R00661X/1.Muonium is a combination of first- and second-generation matter formed by the electrostatic interaction between an electron and an antimuon (μ+). Although a well-known physical system, their ability to form collective excitations in molecules had not been observed. Here, we give evidence for the detection of a muonium state that propagates in a molecular semiconductor lattice via thermally activated dynamics: a muonium polaron. By measuring the temperature dependence of the depolarization of the muonium state in C60, we observe a thermal narrowing of the hyperfine distribution that we attribute to the dynamics of the muonium between molecular sites. As a result of the time scale for muonium decay, the energies involved, charge and spin selectivity, this quasiparticle is a widely applicable experimental tool. It is an excellent probe of emerging electronic, dynamic, and magnetic states at interfaces and in low dimensional systems, where direct spatial probing is an experimental challenge owing to the buried interface, nanoscale elements providing the functionality localization and small magnitude of the effects.Publisher PDFPeer reviewe
- …